Wide-temperature range ester lubricants

ABSTRACT

WIDE-TEMPERATURE RANGE ESTER LUBRICANTS ARE PROVIDED BY PREPARING AN OLEFIN OLIGOMER IN THE PRESENCE OF A BF3PROMOLED CATALYST AND SUBSEQUENTLY REACTING THE OLEFIN OLIGOMER THUS FORMED WITH A COMBINED ACID-BF3 REACTANT TO OBTAIN THE CORRESPONDING ESTER.

United States Patent Oflice 3,809,652 Patented May 7,, 1974 ABSTRACT OF THE DISCLOSURE Wide-temperature range ester lubricants are provided by preparing an olefin oligomer in the presence of a BF,- promoted catalyst and subsequently reacting the olefin oligomer thus formed with a combined acid-BF reactant to obtain the corresponding ester.

BACKGROUND OF THE INVENTION (1) Field of the invention This invention relates to the synthesis of ester lubricant compositions and, in one of its aspects, relates more particularly to their preparation from the carbonium ion associated with olefin oligomerization and a carboxylic acid. These components are useful as hydraulic fluids or lubricating oils, having improved properties of increased viscosity indexes, additive solubility and seal swell when compared with olefin oligomer fluids.

(2) Description of the prior art The prior art has suggested the preparation of olefin oligomers to provide lubricants intended for such use as hydraulic fluids or various forms of lubricating media. Some of the shortcomings of such lubricants reside in either exhibting undesirable inability to provide adequate solubility for additive components or poor capability of providing adequate seal swell.

SUMMARY OF THE INVENTION In accordance with the present invention, wide-temperature range ester lubricants, intended for such use as hydraulic fluids and lubricating oils, having improved additive solubility and adequate seal swell, are provided in the form of esters having the structure mL R J... R

in which R is alkyl or hydrogen and n is at least 2.

Preferably R, in the above structural formula, comprises an alkyl group containing at least about 4 car-bon atoms, and in most applications from about 4 to about 18 carbon atoms.

The preparation of the ester lubricants involves, in general, a process including the steps of olefin oligomerization followed by carboxylic acid esterification. In its more specific aspects, the process of preparing the ester lubricant comprises preparing an olefin oligomer in the presence of BF -promoted catalyst and subsequently reacting the olefin oligomer thus formed with a combined acid-BE, reactant to obtain the corresponding ester. In a preferred modification, following the aforementioned completed reaction, the ester product is quenched and made basic, the basic product thus produced is then water-washed to obtain a neutral product; and the neutral product thus produced is hydrogenated to remove residual olefinic bonds.

In the above described reaction the acids react with the olefin in the presence of the catalysts to form the ester insitu. The reaction for producing the ester may be illustrated as follows:

R-ort cm-on om-b-ob-R H in which R is an alkyl group, preferably containing at least about 4 carbon atoms, and from about 4 to about 18 carbon atoms in most applications, or hydrogen; and n is at least 2. i

In the above-described reaction, the quantity of olefin monomer present is first consumed in order to attain equilibrium in the reaction, while the acid reactant is added for the purpose of obtaining the desired ester. The ester ultimately obtained may be employed as a lubricant per se, or, as previously indicated, the ester product may be employed as a lubricant after hydrogenation of the neu-' tral product. In other instances lubricating media may be employed in the form of oils of lubricating viscosities or as greases having incorporated therein the above-prepared esters or ester products.

DESCRIPTION OF SPECIFIC EMBODIMENTS The following examples will serve to illustrate the novel ester compounds of the present invention, their preparation and eflective utility as lubricants or lubricant compositions.

Example 1 A boron trifiuoride saturated l-decene stream and an ethanol-boron trifiuoride molar adduct were metered separately and simultaneously into a reaction flask fitted with a stirrer, thermometer and condenser. The flask had been previously cooled to 10 C. and pressured with boron trifiuoride to two inches of mercury. This temperature and pressure were maintained throughout the experiment. The pump rates were 3.26 g./min. and 0.033 g./min. for decene and alcohol promoter, respectively. The addition was completed in 46 minutes. The mixture was stirred for four hours at 10 C. and then the boron trifiuoride source was turned off. The mixture was quenched with ml. of 10% ammonium hydroxide, water washed until neutral, filtered and analyzed by gas chromatography (Table I). The monomer and? dimer were removed by distillation using a heated, 12-inch Vigreux column and a take-elf rate of one drop per second. The head temperature during monomer removal varied from 80-105 C. at 50 mm. and for dimer between 125-145 C. at 0.5 mm. The topping of 123 g. of the mixture yielded 118 g. of trimer plus product having viscosity properties as shown in Table II.

Example 2 In an experiment entirely similar to Example 1 except, after 1.5 hours hold the boron trifiuoride source was turned 01f and 19.4 g. (0.19 mole) of trimethyl acetic acid was added and the mixture was stirred at C. for 19.5 hours. It was quenched and worked-up as in Example l. The gas chromatographic analysis before and after the esterification are shown in Table I and the vis cosity properties of the ester fluid are shown in Table II. Infrared analysis confirmed the presence of ester.

' TABLE I '[Olefin oligomerization followed by in-situ'esterificattonl" Oligomer distribution, percent [Viscosities of C decene oligomers before and after esterification] Can olefinic Percent Kinematic viscosity, is at- Trimer Residual 210 F. 100 F. -40 F.

Example The above examples thus serve to show that the esters prepared by the method of the present invention can serve as outstanding wide-temperature lubricants These ester products, because of the polar nature of the ester group'- ing, impart'improved additive solubility and seal-swell, when compared with olefin polymer fluids. v

From the foregoing data and examples, it will be apparent that the above-described esters of the'present invention are markedly effective as lubricants or as components of lubricant compositions. It will also be understood that although the present invention has been described with preferred embodiments, various modifications and adapta- -tions thereof may be resorted to without departing from andin which R is an'alkyl group having from about 4 to about 18 carbon atoms and n is at least 2.

'References Cited UNITED STATES PATENTS 2,862,013 11 1958 Miller et a1 252-56 s 2,936,315 5/1960 Whitaker "2521-56 s 3,299,110 1/1967 Pine 25256 5 3,579,449 5/1971 Wann et a1. 252-4911 X OTHER REFERENCES Murphy et al.: Ind. Eng. Chem, vol. 42 (1950), pp. 2415-2420.

.Cohen et al.: Ind. Eng. Chem., vol. 45 (1953), pp. 1766-1775.

WARREN CANNON, Primary Examiner US. Cl. X.R. 

